Transfer robots are employed in industrial fields, including the manufacture of liquid crystal display panels, to transfer thin workpieces, such as glass substrates. Typically, transfer robots are used to carry workpieces into and out of process chambers in the steps of manufacturing liquid crystal panels.
Some known transfer robots have a sliding mechanism (linear motion mechanism) that moves a hand of the robot along a horizontal linear path. JP-A-2014-65092 discloses an example of a transfer robot having a hand that moves along a horizontal linear path. The transfer robot disclosed in JP-A-2014-65092 includes a moving part mounted on a pair of linear guide rails supported on a guide body (supporting part) and drives the moving part by a belt drive mechanism. The guide body is movable up and down and rotatable. In this linear motion mechanism, the moving part is moved linearly along the guide rails (supported on the guide body) by the driving force supplied from the belt drive mechanism. The moving part is provided with a hand on which a workpiece is to be placed, and the hand is provided with a detection sensor that detects a workpiece placed on the hand.
The detection sensor and a control unit are connected via wiring that is divided into a section located on the guide body and a section located on the moving part. The sections of wiring are connected when the hand extends beyond the guide body to reach a transfer position where a workpiece can be passed or received and when the hand is retracted back to an initial position where the hand rotates. The detection of a workpiece can be performed when the hand is at the transfer position and at the initial position.
Unfortunately, there is a problem that the detection of a workpiece cannot be performed when the hand is at positions other than the transfer position and the initial position. Another problem is that particles may be generated by the wire terminals contacting each other when the sections of wiring are connected. However, constantly connecting the detection sensor and the control unit via wiring may lead to disadvantages. For example, particles may be generated at a sliding section of a cable guide (such as Cableveyor, registered trademark) that stores wires inside, or the sliding section may be damaged. In addition, the cable guide may interfere with the rotational or other motion of the transfer robot. Further, the wiring itself may be damaged or disconnected through repeated bending in different states.